How To Clean Heavy Grime from Concrete
Although caked on grime can seem daunting to remove from any surface, it can appear particularly challenging in an area such as the garage, basement or driveway, where dirt and oil are regularly reintroduced. While caked on grime requires a certain amount of elbow grease to remove, the good news is that it doesn't necessarily require toxic solvents or exotic cleaning tools. Just a bucket, a brush, some soapy water, and, if you like, a detergent booster - and that should be all you need to remove even older caked on grime. Concrete base materials and surface treatments can vary, so even simple methods and materials should be tested in an inconspicuous location before using them in a wider area.
Scrape bulk grime away with a putty knife or other tool, keeping in mind that even concrete can be sensitive to scraping particularly if sealed. In a large bucket, mix about a gallon of hot water and add just enough mild pH neutral dish liquid or powder detergent to make a lightly sudsy solution. Add 1/2 cup of either Oxyclean or Borax to boost alkalinity and make a more effective cleaning solution. Apply the solution directly to the grime-affected area with a nylon bristle brush, scrubbing with moderate pressure. Rinse the brush regularly and refresh the cleaning solution as necessary. Do a clear water rinse to help remove any excess suds and dislodged grime. Blot with clean newspaper. Examine the affected area, and, if necessary, repeat the cleaning process. Particularly stubborn spots can be treated with WD 40 applied with a clean rag and according to manufacturer's instructions, but make sure to wipe away any WD 40 residue with water and mild dish liquid. When the grime has been removed to your satisfaction, rinse with clear water, blot dry with clean newspaper and allow to dry.
Caution: Never mix cleaning agents or chemicals, the result can be dangerous or deadly. Before cleaning, always test the agent on an inconspicuous location to determine its suitability and to make certain it does not damage the material. Wear appropriate clothing such as gloves and protective eyewear, and work in a well-ventilated area. Accidental inhalation or ingestion of cleaning agents can be hazardous and even fatal, particularly to pets and children.